The present application describes a lightweight flexible keyboard formed from a grid of wires encased in an outer sheath.
It is often desirable to make a computer as small as possible. The size of a computer, however, is often limited by the sizes of the input and output devices.
Computer data is often input from a keyboard. Data entry by a keyboard requires a certain minimum size that accommodates the user""s hands and the conventional typing style. Laptops and other portable computers can be made with reduced-size keyboards in order to save on space. However, a typist may often feel cramped by the reduced size of the keyboard.
The present system teaches a flexible keyboard formed of a grid of wires which are position encoded. The flexible keyboard can be folded or rolled when not in use. The grid includes a waterproof cover, including an overlay, including an indication of a plurality of characters, and having a pressing surface allowing pressing against a location at an intersection between two wires of the grid. A position detecting circuit, detects the position of pressing and converts that position of pressing to a character that is represented thereby.
In an embodiment, the keyboard is formed by a grid of wires that cross at locations. The crossing locations define allowable key press locations. An encoding circuit determines the location of pressing based on the wires that are selected.
The grid is wrapped in a waterproof material, with a character set printed on a top surface of the material. Application of pressure at any specific location causes a contact to be made. The position of contact is determined from the encoding circuit, and converted to a letter indicating the position. A look up table can be used to convert between the position and the letter it represents.
In one embodiment, the wires are coated wires with openings in the coating at crosspoint locations to allow them to make contact. In another embodiment, a resistive ladder is used to produce an output voltage that depends on the location of pressing.